Barriers to fish passage, such as such as flood mitigation, drainage structures, and extensive road, rail and canerail networks, can have a significant impact on native fish assemblages. We identified artificial physical barriers in the Wet Tropics bioregion, Far North Queensland, Australia, through a desktop GIS analysis of the stream/river and transport networks. A total of 5,536 potential artificial, physical barriers to fish passage were identified in a stream network of 19,764 km at a scale of 1: 100 000. The Mulgrave (1,076) and Johnstone (1,069) basins contained the highest number of potential barriers, whilst most potential barriers comprised road crossings (66%) and cane rail crossings (18%). Due to the unavailability of consistent datasets at smaller scales, we have not identified artificial physical barriers smaller than 50 m. Hence it is very likely that the total number of potential barriers to fish passage in the region is many times higher. We subsequently prioritised the 5,536 potential barriers, to identify those barriers that will provide the greatest habitat value for native fish species when removed and/or mitigated. A total of 104 potential barriers were identified as high priority for rehabilitation, with the Daintree (32), Mossman (19) and Mulgrave (17) basins having the highest numbers. We recommend that the high priority status and attributes of these 104 barriers be verified on-ground, and that rehabilitation of barriers be experimentally examined as a management strategy to improve native fish movement and reduce invasive fish abundance in the Wet Tropics region.

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